How much room-shaking home theater power can you expect five minispeakers and a pipsqueak subwoofer to deliver? Technological advances have certainly changed my thinking on this matter, but my listening tests proved speaker size still matters when I compared the Boston Acoustics SoundWare XS 5.1, Energy Take Classic 5.1, and Pioneer SP-PK21BS subwoofer-satellite packages.

The Boston SoundWare XS cube satellites are incredibly tiny, just 4.43 inches wide, 4.25 inches high, and 4.43 deep. Each one weighs just 1 pound. The speaker's rear is faceted, so instead of being a six-sided cube, the SoundWare XS satellite is a polyhedron. Its 10 sides make it easier to squeeze the wee speakers into corners. If you place it on a shelf the speaker can be angled up or fire straight ahead. The matching baby Boston subwoofer is a rather plainly finished dark gray box, though its rounded edges soften the look. It has an 8-inch woofer and port mounted on its bottom panel.

When reviewing really small speakers I usually go easy on them at first, and then gently nudge the volume up. With the "Master and Commander" Blu-ray the SoundWare XS was actually pretty adept with home theater bombast, and even the cannonballs crashing through the sides of the wooden ships didn't result in overt distortion. There are definite limits to how loud little speakers and subwoofers can play, but the SoundWare XS did a better job with this Blu-ray than I heard from the Klipsch HD Theater 500. The Boston's subwoofer-satellite blend was so smooth I never heard the sub as a separate sound source (that's a good thing). If you really need the smallest possible home theater speaker system, this is the one to get for around $500.

Great, but for around $400 you can get substantially better sound from the Energy Take Classic 5.1 system. The Take Classic is a six-piece system with four bigger satellites; the Energy sats are 6.8x4.1x4.1 inches. The center speaker measures 4.1x10.25x4.1 inches and weighs 3.2 pounds. The 200-watt subwoofer has an 8-inch woofer; it's a 12.6-inch cube.

I loved the sound of this system. It has a full balance that you only get with a perfectly matched satellite and subwoofer system. The "Wayne Shorter Live at Montreux 1996" fusion jazz concert DVD is the sort of disc that reveals weaknesses of little speakers, but in our testing Shorter's saxophone had a big, rich sound while Rodney Holmes's drum solos were punchy and solid. It's a very dynamic performance, which encouraged me to turn up the volume, and the Take Classic didn't seem to mind. It just sounded better and better as I listened to the high-energy music. Home theater bombast also rocked my world. The little Energy system is a winner.

The Take Classic is really good, but it's no match for the Pioneer SP-PK21BS, which also sells for $400! This time the best-sounding system isn't the most expensive, and it's sold direct from Pioneer with free shipping. The SP-PK21BS system was designed by Andrew Jones, a name known to audiophiles for his work for high-end speaker companies like KEF and Infinity, and on Pioneer's ultrahigh-end TAD Reference speakers. Jones' designs have consistently earned rave reviews in the audiophile press. There is one catch: the SP-PK21BS is absolutely huge compared with any of the competing systems.

How big is it? The SP-BS21-LR bookshelf speakers are 12.6 inches high, 7.2 inches wide, and 8.1 inches deep; and the SP-C21 center speaker is even bigger, at 7.9x19.9x8.7 inches. The SW-8 8-inch subwoofer is average in size for a budget system, being 14.3x12.4x12.4 inches. If you're looking for a "lifestyle"-oriented speaker system, the SP-PK21BS won't be of interest.

But the SP-PK21BS is, without doubt, the best-sounding $400 speaker package I've heard to date. The five speakers' dynamic, powerful, and tonally balanced sound is impossible to duplicate with smaller speakers. The "Black Hawk Down" Blu-ray's biggest battlefield explosions and the helicopter crash's dynamic-range demands were handled with ease. The system could play louder without generating overt distortion than any comparably priced small system. The SW-8 subwoofer's bass was well controlled, but was somewhat lacking in very low-frequency extension; the Bose Acoustimass 6 Series III's much larger sub had a little more oomph down there.

The Energy Take Classic was not embarrassed by a direct comparison with the mighty Pioneer. The difference in sound quality at quiet or moderate volume wasn't all that significant, but the SP-PK21BS still won in terms of clarity, and dialogue sounded more natural. Once I nudged the volume up, the SP-PK21BS pulled decisively ahead; its superior bass definition, dynamic clout, and effortless power made for a far more realistic presentation than the Take Classic could muster. If you like to play movies loud, or your room is bigger than 300 square feet, go for the SP-PK21BS.

If you care more about sound than style, and your speaker budget tops out at $400, the SP-PK21BS is the one to get. It's not just amazing for $400. I'd be just as enthusiastic if Pioneer were charging $500 or $600 for the SP-PK21BS, it's that good.

For a more detailed analysis of these three systems see my complete CNET reviews, linked above.